Privets in the sanctuary, oh my!
We had six Master Naturalists working out in the Heard Sanctuary today, pulling up about 600-700 linear feet of barbed wire in the sanctuary. It was actually more fun than it might sound, since the weather was good, the company of other Master Naturalists is always great, and we got to see some interesting plants, insects, and fungi. We did get into a spirited (but not heated) discussion of the various types of privet growing out there. Parviz has been working hard on getting all the privets out of the sanctuary, but today we were working in a section that he hasn’t yet reached, so we had several samples under discussion. I felt pretty confident about Chinese Privet and Quihoui Privet, except how to pronounce Quihoui (kwee-WHO-ee, according to today’s research.)
EDIT: after some discussion (see comments section below,) I’ve settled on KYOO-ee as the pronunciation I’m going to try to stick with. (But I won’t argue if you want to say it some other way!)
Some people were calling one large specimen Japanese Privet, though, and I’d have called it Glossy Privet. None of them knew the scientific name, so I couldn’t figure out if it was a different species or just a different common name. I’ve been calling all the large-leaved privets I’ve seen Ligustrum lucidum (Glossy Privet), but there is a L. japonicum, so if we had it in the sanctuary, I wanted to know. (Most everyone elsewas of the opinion that, no matter what we called it, it needed to come out, so what did it matter? But inquiring minds need to know!) After an hour or so in my FNCT, here’s what I’ve come upAll of the privets growing here are introduced invasives which have escaped from cultivation. They are shrubs or small trees, evergreen or semi-deciduous, and have opposite leaves. (The opposite leaf attachment is the first thing to check for if you suspect privet. See more about oppositely-attached leaves below.*)
Two common types of privet have glabrous twigs and large leaf blades, 2.5-6" long. These are both evergreen.
• The first of these is Glossy Privet, Ligustrum lucidum. It can grow to be a tree up to 30 ft. tall, or occasionally taller. Glossy Privet leaves are large, 3-6" long, with 6-8 or more distinct veins on each side of the midrib. The leaves are glossy and hairless. Glossy Privet leaves taper to a narrow point and the petiole (stalk) of the larger leaves is up to 3/4" long. In the flowers, the tube of the corolla equals the lobes in length.
• The second of the large-leaf privets is Japanese Privet, L. japonicum. It is a smaller shrub or small tree, usually not much more than 10 ft. tall. The leaf is somewhat smaller than that of Glossy Privet, up to about 2.5 -4" long. Leaves have only about 4-5 indistinct veins on each side of the midrib. The leaf shape is less pointed than that of L. lucidum, and it has a shorter petiole, usually less than 1/2" long. (*New note: according to texasinvasives.org: Japanese Privet does not tend to escape cultivation, so maybe I haven't been wrong in calling the wild specimens of large-leaved privets I've seen Glossy Privet.)
Two other common types of privet have pubescent (fuzzy/hairy) twigs and small leaves. These are semi-deciduous, evergreen in mild winters.
• The most widespread invader is Chinese Privet, Ligustrum sinense . It is a shrub growing to about 12 ft. tall. Its leaves are 1 - 2.5" long and usually hairy along the midrib on the underside. The leaf shape is a rounded diamond or an egg shape. The flowers are in compact clusters, with the corolla tube shorter than the lobes.
• The other small-leaf privet is Quihou Privet, L. quihoui. The leaves are 1 - 2.5" long, dark green, usually oblanceolate (teardrop shaped, narrowest near the stem) and hairless on the underside. The leaf base tapers all the way to the twig, appearing to have almost no petiole. Flowers are in whorl-like, separated clusters at tips of branches and on paired side branchlets, forming into loose clusters. The corolla tube is about equal to the lobes.
After I finished the above, I happened to find a couple of handy guides to the privets at Texasinvasives.org. So I guess I could have saved myself the trouble, but I don't think I'll ever again get mixed up about these four privets! Each of these is a one page pdf: the first has pictures, the second a chart with more information.
https://www.texasinvasives.org/invaders/CS_Resources/PrivetKey.pdf
https://www.texasinvasives.org/invaders/Trainer_Resources/Ligustrum.pdf
*Privets are one of the few trees/shrubs around here (North Central TX) that have oppositely-attached leaves. Here's the acronym we use for remembering the most common woody plants with oppositely-attached leaves:
DAMPeR:
D - dogwood (in North Central TX, that would be Roughleaf dogwood.)
A - Ashes (around here, Green Ash, White Ash, Texas Ash)
M - Maple (around here, only Ash-leaved Maple, aka Boxelder Maple, or just Boxelder)
P - Privets
R - Rusty Blackhaw
Ashes and Boxelder both have compound leaves, so those should be easy to rule out. Rusty Blackhaw leaves have toothed margins, and privets have smooth margins, so that should be easy to rule out, too. Roughleaf dogwood does have smooth margins and simple, oppositely-attached leaves, like the privets. Dogwood leaves are thinner, and ours have a rough texture - hence the name!
Two other plants whose leaves resemble privets in shape and texture are the hollies: possumhaw holly (Ilex decidua) and yaupon holly (I. vomitoria). Just remember to check for the leaf attachment. Hollies have alternately attached leaves, rather than the oppositely-attached leaves of privets.
